Reviving an old thread as I’m considering this very upgrade. I notice many reference buying their KT150’s on eBay. Meanwhile Upscale passionately states that their tubes are somehow blessed with a veritable dose of unobtanium and are well worth the higher price. The junk discarded by others are ebay fodder, or some such.
Considering their impressive cost, is there merit to spending extra for the Upscale touch or is it just marketing? Currently looking at $155+ per tube.